Safety diaphragm



Oct. 12, 1937. AQJ. NERAD 2,095,828 I SAFETY DIAPHRAGM Filed April 16, 1936' Figi l n E n hve'ntor: Anthony J. N vnd.,

Hi Abtor'neg.

Patented Oct. 12, 1937 UNITED STATES SAFETY DIAPHRAGM Anthony J. Nerad, Schenectady, NfY., asalgnor to General Electric Company, a corporation o! New York Application April 16, 1936, Serial No. 74,805

1 Claim.

This invention relates to safety diaphragms for use in connection with tanks or containers for containing fluid such as condensers for condensing steam or other iiuid discharged from a turvbine or the like. These safety diaphragms are -provided as a safety means to protect such tanks or containers in case the pressure to which these tanks are exposed should assume dangerous values. 'I'he safety diaphragm is usually in the form of a thin plate of non-metallic material which breaks or bursts in case the pressure within the tank or container reaches a certain value.

'I'he object of the present invention is to' provide an improved construction and arrangement of safety diaphragms whereby breaking of the diaphragm and consequently relieving the pressure in the tank to be protected is assured at a substantially fixed pressure while using a stronger, stabler and cheaper material for the diaphragm.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing, Fig. 1 illustrates a safety diaphragm arrangement embodying my invention in connectionwith a mercury vapor condenser; and Fig. 2 is an enlarged view of a portion of Fig. 1.

Mercury vapor condensers are used to condense mercury vapor exhausted from the last stage or stages of mercury turbines. Failure of the supply of the condensing agent, in this case water, may result in high pressures of destructive magnitude in the condenser. Often the mercury vapor is associated with other gases, for instance hydrogen, which under certain conditions may lead to explosion rendering it necessary to protect mercury vapor condensers.

Referring now more specifically to Fig. 1, the arrangement comprises a mercury vapor condenser ID which has an open wall portion II secured to a chamber I2. The latter comprises van outer cylindrical wall I3 and end plates I4 and I 5 Welded to the outer cylindrical wall. u The plate I4 is secured to the open wall portion II by a weld I6. The end plate I5 has an opening I1 connected to a discharge conduit I8 which may -siderably below atmospheric pressure.

(Cl. 22o-89) welded to a holding ring 22. The latter is securely held and tightened together with the end plate I4 by a plurality of bolts and nuts 23. The pressure vwithin the condenser is normally con- Hence, one side of the diaphragm is subject to sub-atmospheric pressure, whereas the other side of the diaphragm in the present instance is subject to atmospheric'pressure, the pressure difference tending to force the diaphragm which may have a diameter of the order of 20 inches into the open wall portion Il ofthe condenser. In order to relieve the stresses thereby set up in the diaphragm, I provide a support for the central portions of the diaphragm or, from another viewpoint, for reducing movement of the diaphragm towards the condenser IIJ. This support is in the form of a grid 24 closely spaced'with the diaphragm and securely fastened to the end plate I4 by means of a plurality of screws 25. During normal operating conditions the side of the diaphragm facing the condenser engages the grid 24. If during operation the pressure in the condenser for some reason, for instance, an explosion therein, increases to a certain extent, the diaphragm is forced outward against the atmospheric pressure until it bursts. In accordance with my invention I provide means in the form of a knife member or members to cut open the diaphragm as it is forced outward a certain extent. This knife or cutting member in the present instance is in the form of a ring 2'6 slightly spaced from the left-hand or outer side of the diaphragm and secured to a shoulder formed on the holding ring 22 by an annular weld 21. 'I'he cutting edge of the ring adjacent the diaphragm is sharp and preferably provided with cutting teeth 28, as shown in Fig. 2. With this arrangement a considerable portion of the diaphragm is cut out by the knife 21 as soon as the diaphragm is moved outward a certain distance in response to a predetermined increase in pressure in the condenser.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent in the United States is:

A safety diaphragm arrangement for mercury vapor condensers including the combination of a chamber having an open 'end plate for connection with an open wall portion of such condenser, a grid member secured to the opening in said end plate, means including e. thin metal plate on the side of the grid member facing away from the condenser to close completely said opening, a cutting element adjacent the diaphragm on the side of the diaphragm facing away from the condenser to cut open the diaphragm as the latter is forced outward in response to e. predetermined increue in pressure in the condenser, and a ring bolted to the end plate to support the cuttina' element and to force an outer edge portion of the thm metal plate into mud-tight remtin with the end plete.

ANTHONY J. NERAD. 

